Blood treatment devices are extensively used in medicine, providing an extracorporeal blood circuit to direct blood to a treatment device from the patient, and then to return the blood to the patient. Some treatments involve separate, so called arterial and venous lines. Other treatment sets define a shared line to flow treated and untreated blood to and from the body.
The largest of this category in terms of the volume of use comprise devices having membranes in the flow treatment device. Such treatment devices include hemodialysis units, plasmapheresis units, hemofiltration units, and membrane-type blood oxygenators for open heart surgery. Also included are bubble-type oxygenators and other, more exotic blood treatment devices, where the blood may pass across a unit which carries a fixed bed of enzyme or other bioactive agent for various forms of blood treatment which are at the present time largely experimental.
While most reference herein will be directed to hemodialyzers, it is to be understood that other flow-through blood treatment devices are intended for modification in accordance with this invention.
The extracorporeal circulation of blood is a complex process. With hemodialysis, a membrane dialyzer is attached to a hemodialyzer hardware unit for providing dialysis solution, and controlling the parameters of blood flow through the membrane dialyzer. The dialyzer is connected at its respective arterial and venous blood flow ports with an arterial set and a venous set at one end of each, while the arterial and venous sets are connected to typically the fistula of a patient at the other set ends, to provide the circulatory flow path of blood from the patient, through the dialyzer, and back to the patient.
Such arterial and venous sets of the present technology carry connected branch lines, which connect the set to various important ancillary functions of the dialysis operation. Specifically, one of the branch connection lines connects with a source of anticoagulant such as heparin. This source typically comprises a syringe which may be controlled by the dialyzer hardware unit to provide a proper heparinization of the blood, to prevent clotting in the dialyzer or other blood treatment unit. Other branch lines connect with a pressure monitor(s). Another branch line from one of the sets typically connects with a container of intravenous quality saline solution for priming of the set, flushing it out, and for the emergency addition of saline to the patient in the event of a crisis brought onto the patient by excessive ultrafiltration.
Also, the sets may have a branch tubing extending from a blood chamber of the sets to which a syringe may be connected, to add or remove air to adjust the blood level in the chamber.
The present arterial and the venous sets are provided separately from the membrane dialyzer, and rather remind one of a spider web, being complex to manufacture and complex to set up in the clinic.
Traditionally, the known blood tubing sets have exhibited disadvantages including the following:
Conventional sets for flow-through blood treatment devices such as hemodialyzers are typically expensive to manufacture. The two dialysis sets needed for a conventional hemodialysis may have more than twenty feet of tubing and over seventy parts, which must be assembled together in a multi-axis array because of the requirement for branch tubings and the like. Thus, the cost effective automation of the manufacture of such sets is not practical, due primarily to the number of components in the sets and the complexity of the various branch connecting tubes which come off of the blood pathway tubing.
A reason that such conventional sets for blood handling are expensive and complex is that they generally must be set up to receive every user-connected ancillary device that a physician might prescribe. However, less than the maximum number of such ancillary devices are typically prescribed in any given treatment, so that some of the branch tubings or other connectors go unused. However, due to the difficulty of stocking and manufacturing the wide variety of different designs that would be required if sets were made for each different physician-dictated procedure, the wasteful practice of providing all branch tubings that may possibly ever be needed is tolerated. To do that is cheaper than administering the vast number of alternate design sets that would otherwise have to be provided.
As a further disadvantage, the branch tubings and connectors extending off of the blood tubing can each tend to provide a stagnant site for blood to collect, which can aggravate clotting problems. By this invention, these stagnant sites can be substantially eliminated from the branch connections which are present.
Also, most branching and ancillary lines of blood handling sets include an on/off tubing clamp to isolate the blood pathway, with these tubing clamps being clamped or manipulated during the dialysis procedure. Such clamps are relatively expensive, and are prone to misclamping errors such as partial clamping or accidental, spontaneous opening. Thus, a branching ancillary line of a conventional blood handling set may accidentally open during a dialysis procedure, for example, when the branching line is not even connected to anything. This of course may result in the spilling of blood in positive pressure sections of the blood pathway, and unsterile air incursion into negative pressure blood pathway sections.
Also, just as the conventional blood handling sets are expensive to manufacture, they are time consuming for similar reasons to prepare for use. As a further disadvantage, the conventional blood handling sets are not cost effectively reused because of their complexity, and also because of the stagnant blood which can clot in the branch lines.
Also, conventional blood lines carry elastomeric injection sites which communicate with the blood flow pathway, for blood sampling or medicament infusion via a syringe and needle. It is known for these injection sites to have been put to emergency service as an access for pressure monitoring and the like via a needle which is connected to a tube communicating with a pressure monitor or the like. This occurs when a permanently connected branch tube has clotted or otherwise failed.
This prior art has many disadvantages. The above needle is exposed and dangerous. Also, the needle is not lockable to prior art, unlockable injection sites, and often falls over even when taped. The injection site cannot then be used for its original purpose. The prior art injection site is not placed where heparin infusion, arterial post pump monitoring, etc. is best accomplished.